for our team from boston to washington, i'm brian williams, nbc news, new york. >>> we've been listening to the nbc news special report on the fbi briefing in boston for the latest developments on the boston marathon bombing. let's go back to cnbc's senior correspondent scott cohen on the ground in boston for the past few days. what did you make of the appeal to the public of two photos of suspects here? >> well, brian williams said it best, it's a forced multiplier, but brings in extra tips, but they don't mind that. they'd rather have more than less. and the other thing, it does fill in some of the blanks of yesterday. they -- the special agent said, yes, yesterday they had identified from the video a person of interest. well, that turned into reports of an arrest, somebody about to be arrested, somebody in custody, they solved the whole thing, no, they found a person of interest and linked that to this other person. and now are determining both of them to be suspects. we will also have video that we will get of -- that is playing. and also, i think that you also -- you'll also want to